Four people were killed in a bullet-riddled rampage across Santa Monica, Calif., that apparently ended with the suspected shooter also dead amid gunfire on a college campus, police said.

The suspect died after a shootout at Santa Monica College, police said, but authorities were investigating approximately nine crime scenes across the city believed tied to the spree. Five to seven of those crime scenes apparently involved gunshots fired, Santa Monica Police Sgt. Richard Lewis told reporters late Friday.

In addition to the dead, at least five people were injured, police said. They included one critically injured person whose life was in jeopardy, a person hospitalized in serious but stable condition and three people sent to hospitals with less serious injuries, Lewis said.

Santa Monica Police Chief Jacqueline Seabrooks initially said "as many as six" victims, plus the suspected gunman, had been killed in the rampage. But police later lowered the death toll to four dead, plus the suspect. Lewis suggested the initial overcount may have been caused by overlapping witness reports of the same fatalities.

Lewis said the motive for the shootings remained under investigation, but police expected to be able to have more details on the suspect and the circumstances of the crime at a news conference planned for Saturday.

"We don't know what sparked this incident, if it happened 10 minutes before, if it was spur of the moment, if it was planned out. We don't know that," Lewis told reporters late Friday.

Authorities first responded to a report of shots fired at 11:52 a.m. PT and found a house on fire. The found two dead bodies inside, fire officials said.

"While conducting a primary search, we found multiple victims," Santa Monica Fire Chief Scott Ferguson said, according to ABC News Radio. "It was clear that they were fatalities and, as such, in order to preserve the crime scene, our firefighters mitigated the fire and backed out in order to preserve evidence."

Police later said the suspect may have had a relationship to the two people found dead in the burning house, but would not specify what the relationship was.

At the same time as the house fire, authorities received reports of a carjacking and multiple shootings now believed related, according to police.

When officials encountered a suspect, he took off towards Santa Monica College.

"There was an exchange of gunfire at that time and the suspect attempted to evade the officer by running off to the college campus," Seabrooks said.

The suspect made his way towards a library, where he shot at least one woman and then went inside, pursued by law enforcement, police said.

"He continued to shoot at them," Seabrooks said. "The officers came in and directly engaged the suspect, and he was shot and killed on the scene."

In 911 calls, the shooter was described as armed with several weapons and possibly a long gun or shotgun.

Seabrooks said the suspect used an AR-15 assault rifle, though Lewis later qualified the description.

"It's an assault-type rifle," he said. "I don't want to go as far as to say it's an AR-15, but that is the style of rifle it is."

Elsewhere on the campus, a person of interest was taken into custody, then released when his claim not to be involved checked out, Lewis said.

"He is not a suspect in this case," Lewis said. "At this time, we believe it is a single gunman and that part of it has been resolved."

Two female victims were hospitalized at Ronald Reagan UCLA Medical Center -- one in critical condition in an intensive care unit and one in fair condition, the hospital said in a news release this evening.

Another victim brought to the hospital died after suffering primarily abdominal injuries, said Dr. Marshall Morgan, UCLA Medical Center's chief of emergency medicine.

Three other women with relatively minor injuries were treated and released at UCLA Medical Center, Santa Monica, the hospital said.

The college campus went on lockdown following the shootings as police attempted to secure the scene -- which Lewis said police accomplished when they determined the only suspect in the shootings was dead.

"The school is not on lockdown," he said late Friday. "It is closed, obviously, because there are numerous crime scenes along the campus. The city of Santa Monica is very safe."

Santa Monica College student Sam Luster was preparing for a presentation in the school's library when he heard gunfire.

"We didn't know what was happening until all the students at the entrance of the library started running down towards the bottom of the library," Luster told ABC News Los Angeles station KABC.

Luster took cover under a desk before moving towards an exit. He said he heard multiple gunshots near the exit.